Create a module and add a method that you call periodically and throw the following code in. To get started [create your own magento module][1] and then you can use the code below to read a CSV file and set properties on the magento products.
// prepare to load products
$product = Mage::getModel('catalog/product');
// read CSV file and load each product and update quantity
$row = 1;
if (($handle = fopen("stockfile.csv", "r")) !== FALSE) {
while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
$sku = $data[0];
$qty = (int)$data[1];
// try and load the SKU
$p = $product->loadByAttribute('sku',$sku);
if ($p) {
// get product's stock data such quantity, in_stock etc
$productId = $p->getIdBySku($sku);
$stockItem = Mage::getModel('cataloginventory/stock_item')->loadByProduct($productId);
$stockItemId = $stockItem->getId();
$stock = array();
// then set product's stock data to update
if (!$stockItemId) {
$stockItem->setData('product_id', $product->getId());
$stockItem->setData('stock_id', 1);
} else {
$stock = $stockItem->getData();
}
$stockItem->setData('qty', $qty);
if ($qty > 0) {
$stockItem->setData('is_in_stock', 1);
} else {
$stockItem->setData('is_in_stock', 0);
}
$stockItem->setData('manage_stock', 1);
$stockItem->setData('use_config_manage_stock', 1);
// call save() method to save your product with updated data
try{
$stockItem->save();
$product->save($p);
} catch (Exception $ex) {
// handle the error here!!
}
unset($stockItem);
unset($p);
} else {
fwrite($fh, "SKU not found: ".$sku."\n");
}
}
fclose($handle);
}
[1]: /2011/02/creating-magento-module/